


Impulse

by JustAFigment



Series: MariChat May Drabbles [3]
Category: Miraculous Ladybug
Genre: "Studying", F/M, Learning things under intense situations helps with remembering, Marichat, Marichat May, Physics, Studying, i think, making physics fun, sin - Freeform, sure lets go with that, this is a sin fic
Language: English
Status: Completed
Published: 2017-05-04
Updated: 2017-05-04
Packaged: 2018-10-27 22:47:54
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,522
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10818351
Author URL: https://archiveofourown.org/users/JustAFigment/pseuds/JustAFigment
Summary: Chat Noir helps Marinette with her physics review, and Marinette learns why it's his favorite subject.Marichat May Day 3 - Homework





	Impulse

“Impulse.”

****

 

  


 

“The change in momentum of an object.”

  
  


 

 

“Good. And momentum?

 

 

  
  
“The product of the mass and the velocity of an object.”

 

 

“Perfect.” Too soft lips brushed softly over Marinette’s shoulder. She could feel him leaning closer to her, the heat trapped between them in that instant before his chest met her back. “Now, what can you tell me about impulse?”  


“W-well, impulse occurs when force is applied to an object over a period of time.” She felt his hands snake around her waist slowly. Chat hummed in affirmation. He closed the book in in her lap, moving it to the side on her bed. She swallowed a shiver of excited apprehension. He was using _that_ method tonight. She went on. “Force is the rate of change of momentum.”

****

His palms were on her thighs, rubbing gently as he settled his chin against her shoulder. It was an unfair study trick, but so far it had never failed to leave a lasting impression. Though, it did make test taking a bit more nerve wracking for reasons completely unrelated to the class in question.  
  
“Correct, princess.” She could hear the smirk in his voice, even without turning to look at him. “Now…” The tips of his fingers tapped a simple pattern against her legs. “What is the momentum of an object with a mass of two kilograms, and a velocity of forty meters per second?”

****

She was thankful that was an easy question. Just a simple matter of multiplication, now that she had the formula memorized. “Eighty kilogram-meters per second.” She replied without missing a beat. Her breath hitched as one of his hands slid up under the white, dotted cotton of her shirt, claws delicately draging featherlight trails up her skin. It was a correct answer and she knew it.

****

His other hand was slowly but surely drifting towards the valley of her legs, his thumb rubbing slow circles against the fabric of her pajama pants. If she gave in, he’d pull away.  It was all part of this little game they’d started ages ago. It started out that a correct answer would win her a quick kiss on the cheek, or shoulder. A few times later it was a gentle caress, or a shoulder rub. He’d offer to massage her hands for her after a long sketching session. Then he found her lips and they became longer. Deeper. Desperate.

****

For a short while their study sessions became entirely unhelpful.

****

But tonight it was imperative that Marinette grasp the concepts on the table. Tomorrow was the exam for that particular unit, and she had missed more than an acceptable number of classes the last two weeks due to very poorly timed akuma attacks.

****

“Next question.” He let his fingers press gently between her legs, petting through the thin fabric in a manner that, had it been anywhere else on her person, would have been entirely soothing. Instead it managed to make it entirely too hard to focus on the words being uttered beside her head in hushed, husky tones. “A force of thirty thousand Newton is exerted for four seconds on a ninety-five thousand kilogram mass...” He waited and she nodded. Thirty thousand Newton, four seconds, ninety-five thousand kilograms. “What is the impulse?”

****

The hand against her stomach drifted upwards and her breath hitched at his knuckles ghosting just beneath her breasts. Again, simple multiplication. “Hundred twenty thousand...” Instead of inching higher still his arm wrapped more tightly around her, pulling her tight against him.

****

“What’s the mass’s change in momentum from that impulse, hmm?” The other hand played at the hem of her pants.

****

She hesitated. A change in momentum. Her chaton had never been quite so bold, but his propensity for puns and wordplay was certainly coming into play tonight. It was such an easy question though. It was a loaded question. It had to be. Marinette could feel his heart and hers were waging battle against one another, which would beat out of it’s cage first. If she got it wrong, he’d back off. But it was so simple. He knew she knew it.

****

He was offering her an out.  
  
“It’s the s-same...” She breathed. Her arms shifted from where they’d been lightly, tensely resting against her own knees, her hands landing against his instead. His own moment of hesitation hung between them for only a moment before his fingers dipped beneath the hem of her pants, neither of them breathing.

****

Marinette sucked in a gasp as he traced down the line of her lips and she tilted her head back against his shoulder. He let out a shuddering breath against her neck, kissing the pale skin over and over and peppering as much of the exposed area as he could. With a bit more pressure his finger dipped just inside, brushing against a taut bead of nerves. She bit her lip to hold in a tiny whimper.

****

“What’s the mass’s change in velocity from this impulse?” Her eyes snapped open. He was still going?  
  
“Really?” She whined, a little incredulous.

****

He pulled his hand away and she wanted to smack him. “Well, if you want to quit studying…?”

****

She gaped at him. Or rather, at the ceiling. She hadn’t bothered to turn her head. He was incorrigible sometimes. It wasn’t at all hard to tell he was smirking. He seemed to only ever have three modes. Unadulterated smirking flirt, cheeky cheesy goofball, and enough-sense-about-him-to-be-ashamed apologetic. Right now, he definitely wasn’t either of the last two. Marinette huffed in defeat, but was rewarded a moment later when his finger returned with the added bonus of rubbing near painfully slow circles against the nub. And now she had to try and compute math.

****

Or she could just enjoy herself for as long as it took for him to figure out she was stalling. It probably wouldn’t take long, but still.

****

“Princess...” No, it didn’t take long at all. Clever cat.  
  
“One point two six meters per… second.” She groaned softly. That sinful finger of his increased it’s speed. Just a fraction. Just a deliciously torturous fraction.

****

“Excellent. Why wouldn’t we be able to find the change in kinetic energy of the mass?” He threw her a curveball. Why would he do that? That wasn’t very fair.

****

She racked her brain, trying to think back to the initial problem, rolling it over and over in her mind and fighting back all the tiny spasms his finger was trying desperately to pull out of her. “Uhm...” She took a deep cleansing breath. “Uh… We… We don’t know th-the starting velocity?” Right? He never gave her the velocity in the initial problem. There wasn’t enough information for that answer.

****

“Don’t we?” He was still smirking, but he didn’t stop. “No, I guess we don’t, do we. Alright then.” He nipped her neck, and she jumped. “Last question.” His voice dropped to a dangerous tone.

****

Oh no…

****

“When an increase in speed doubles the momentum of an object...” Her whole body jerked as his finger mimicked his words, the slow tentative circles suddenly jumping to something intense and borderline desperate. Marinettes hands gripped hard at his legs and she stifled a yelp at the startling shift in pace, swallowing it down into a guttural moan. “What happens to the object’s kinetic energy?”

****

“Chat!” She screwed her eyes shut tight as he clung to her, holding her firmly in place against him.

****

“Does it ‘A’,  increase, but not quite double?” She whined, her legs shaking as heat built inside, low and fast. She shook her head.

****

“What about ‘B’, doubles equal to the increase in speed?” She was panting, her head still shaking at the incorrect answer and managing to stutter out something akin to the word ‘no’.

****

Her body shuddered against his, hips jerking along with the motions of his hand down her pants. She whimpered as everything coiled tighter and tighter inside of her, inside her mind. She knew she was panting through her teeth, an utter mess, pressing back desperately against her partner. She didn’t care.

****

She just wanted him to get to the last damn answer already.  
  
“Well, there’s always ‘C’-”

****

“Yes, C!” He was grinning against her skin. She could feel it. “M-more than doub- _les._ ” She yelped. He bit her shoulder. He actually bit her shoulder. But it was enough.

****

She could already feel herself coming undone, biting her lip against a straining moan, her hands flying to his as her thighs clamped shut around his hand, a full body tremble rolling through her with an intensity that left her boneless and breathing heavier than most battles failed to do.

****

The world dazzled behind her closed eyes as Chat Noir hugged his study partner delicately to his chest. Oh so slowly he pulled the incriminating hand free from her own, her arms resting limp in her lap. She gave the smallest startle as she _heard_ him lick himself clean.

  
She didn’t have the the vocabulary to describe how red she knew her cheeks must have been at that exact moment.  
  
“You know, Marinette, physics always _was_ my favorite subject.”

**Author's Note:**

> MOST OF THE PHYSICS TALK came from this online review page because I don't remember anything about physics from high school. http://www.physics247.com/physics-homework-help/ .php I found the review questions INCREDIBLY HELPFUL 9 w 9


End file.
